An analytic approach to smooth polynomials over finite fields

Abstract. We consider the largest degrees that occur in the decomposi-tion of polynomials over finite fields into irreducible factors. We expand the range of applicability of the Dickman function as an approximation for the number of smooth polynomials, which provides precise estimates for the discrete logarithm problem. In addition, we characterize the dis-tribution of the two largest degrees of irreducible factors, a problem relevant to polynomial factorization. As opposed to most earlier treat-ments, our methods are based on a combination of exact descriptions by generating functions and a specific complex asymptotic method.